Crystallizing machine

ABSTRACT

A machine for crystallizing a thermoplastic preform or container is constructed from modular subassemblies and utilizes a preheated plug to provide the sole upright support for a workpiece in the crystallizing process. The first modular subassembly includes the workpiece in-feed and plug preheat structures and incorporates the drive apparatus for the entire machine. The opposed end of the crystallizing machine is constructed of a subassembly which operates to provide the turnaround and tensioning takeup for the carrier mechanism transporting the workpieces. Positioned between the first subassembly and the opposed end subassembly are heating and cooling processing modules which can be provided in any number depending on the size constraints and workpiece quantity restraints desired. The processing modules provide the heating and crystallizing processes for the desired area of the workpiece and the cooling process of the workpiece prior to unloading.

This application is a Continuation of Ser. No. 09/349,047 filed Jul. 7,1999, now U.S. Pat. No. 6,139,812.

TECHNICAL FIELD

This machine relates to a process and apparatus for use in strengtheningthe finish area of a hollow blow molded container manufactured from athermoplastic, such as a thermoplastic polyester or a biaxially orientedpolyethylene terephthalate resin.

BACKGROUND ART

A hollow blow molded thermoplastic, such as a thermoplastic polyester ora biaxially oriented polyethylene terephthalate resin, “PET”, container,commonly used to contain food or beverage, has excellent physicalproperties, durability, and a wide range of applications. However, whenused in hot-fill applications, certain portions of the container whichare not subjected to the biaxial orientation during the blow moldingprocess, such as the neck area seal edge or thread, commonly referred toas the finish area, are found to soften and deform in an undesirablemanner because the temperature of the food or beverage fill is oftenabove the glass transition temperature of the plastic. Manymethodologies and processes have been tried in attempts to strengthenthe neck area of such containers by enhancing the density of the resinand opacifying and whitening the neck due to the crystallization of thethermoplastic resin by heat treating the neck.

Strengthening the neck area of a thermoplastic container greatlyincreases the craze resistance of the neck area, improves the mechanicalrigidity and increases impact resistance, wear resistance, and externalpressure resistance of the container. However, a common side effect ofsuch a thermal treatment of the neck area of the container is anundesirable deformation of the neck area, thus leading to problems withcapping and sealing the container.

U.S. Pat. No. 4,476,084 provides a solution to the problem ofdeformation during heat treating by placing a cold die pin or plug intothe bore of the neck prior to heating. The cold die pin assists inmaintaining the proper size and shape of the neck during thecrystallization process. Others have found similar solutions. See, forexample, U.S. Pat. Nos. 4,388,356, 4,379,099, 4,572,811, 4,590,021 and5,261,545. The use of such cold plugs and dies however have led toproblems when speed of manufacture is a priority. Inefficient heating,failure to properly position the plug and deformation of thethermoplastic container due to the weight of the plug have commonly beenexperienced, thereby leading to a further search for a fast, efficientway of crystallizing the neck area of the thermoplastic container.

BRIEF DESCRIPTION OF THE INVENTION

The crystallizing machine and its process of this invention improvesupon the efforts of the prior art in many ways. The machine makes use ofa preheated plug which is inserted into the mouth or neck of athermoplastic preform or container, commonly known as a workpiece. Whilethe workpiece is described herein as being a thermoplastic, it ispreferable that it be a thermoplastic polyester, and even morepreferable that it be polyethylene terephthalate (PET). For the purposesof this description, references will be made to PET workpieces. However,this description is not intended to be limiting on the inventiondescribed herein. The workpiece is carried solely in an upright positionby the preheated plug through the crystallizing process. The preheatedplug assures even and efficient heating when crystallizing the finisharea of the workpiece and constrains the shape of the finish area to apredetermined size and shape during the crystallizing process.

The crystallizing machine of the present invention is constructed frommodular subassemblies. The first modular subassembly includes theworkpiece in-feed and plug preheat operations and incorporates the powersource and drive apparatus for the entire machine. The opposed end ofthe crystallizing machine is constructed of a module or subassemblywhich operates to provide the turnaround and tensioning for thetransport member carrying the workpieces. Positioned between the firstmodular subassembly and the opposed end modular subassembly are heatingand cooling processing modules or subassemblies which can be provided inany number, depending on the size constraints and workpiece quantityrestraints desired. The processing modules provide the heating andcrystallizing processes for the finish area of the workpiece and thecooling process for the workpiece prior to unloading.

For the purposes of the following description of the preferredembodiment, reference will be had to the following drawings and thecrystallizing machine of the present invention will be described ashaving four subassemblies. However, the description of the invention isnot intended to be limiting upon the scope of the claims which follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a right side elevation view with cutaway of the crystallizermachine of the present invention.

FIG. 2 is a right side elevation view with cutaway of the crystallizermachine of the present invention with access doors removed.

FIG. 3 is a left side elevation view with cutaway of the crystallizermachine of the present invention.

FIG. 4 is a left side elevation view with cutaway of the crystallizermachine of the present invention with access doors removed.

FIG. 5 is a cutaway right side elevation view of the processing modulesof the crystallizer machine of the present invention.

FIG. 6 is a cutaway left side elevation view of the processing modulesof the crystallizer machine of the present invention.

FIG. 7 is a top view with cutaway of the crystallizer machine of thepresent invention.

FIG. 8 is a front elevation view of the preheat, pickup and drive moduleof the crystallizer machine of the present invention.

FIG. 9 is a detail side elevation view of the preheat, pickup and drivemodule of the crystallizer machine of the present invention.

FIG. 10 is an elevation view of the in-feed apparatus of the preheat,pickup and drive module of FIG. 9.

FIG. 11 is an end view of the workpiece stripper of the in-feedapparatus of FIG. 10.

FIG. 12 is a top view of the in-feed apparatus of FIG. 10.

FIG. 13 is a back elevation view of the processing modules of thecrystallizer machine of the present invention.

FIG. 14 is a detail elevation view of the preheating source used in thecrystallizer machine of the present invention.

FIG. 15 is a detail elevation view of the cooling source and the heatingsource used in the crystallizer machine of the present invention.

FIG. 16 is a detail elevation view of the cooling source used in thecrystallizer machine of the present invention.

FIG. 17 is a perspective view of one embodiment of a workpiece pickupplug of the crystallizer machine of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 1-6, the crystallizer machine of the presentinvention as described herein is shown to have four modular sections.The number of modular sections can be varied as desired by increasingthe number of processing sections, as shown in FIGS. 5 and 6, in orderto meet design demands for workpiece size, material and speed ofoperation. For the purposes of this description, the crystallizermachine will be described as having four distinct modular sections: thepreheat, pickup and drive module 10 as shown in FIGS. 1-4; the takeupmodule 11 as shown in FIGS. 1-4; and the heating and cooling processingmodules 12, 13 as shown in FIGS. 5 and 6. The modules of thecrystallizing machine are designed to provide a mezzanine level 14, whenjoined together into a single operative machine. The mezzanine level 14carries the cold air generating units 15 and blower fan units 16 andprovides a walkway 17 for the operators. The mezzanine level 14 isaccessible by a ladder or step assembly 18 provided on the end of thepreheat, pickup and drive module 10 and includes safety railings 19provided about the perimeter of the mezzanine level 14. The floor of themezzanine 14 incorporates a hot air plenum 21 and a cold air plenum 22as shown in FIG. 13.

Access doors 20 are provided on the front and back of the preheat,pickup and drive module 10, as shown in FIGS. 1 and 3, which whenopened, provide access to the machinery contained within the module 10and when closed, provide a safety barrier. The access doors 20preferably have glass windows through which the operator can observe themachinery operation.

Referring again to FIGS. 1 and 3, the takeup module 11 includes a pairof top access doors 23 located on the front and back of the module 11and a set of bottom access doors 24 also located on the front and backof the module. The access doors 23, 24 when closed, facilitate themaintenance of desired internal atmosphere regulation, as it relates tothe heating and cooling in the crystallizing process. The access doors23, 24 are also used as safety shields when the machine is in operationand provide access to the internal machinery when opened.

Referring also to FIGS. 1 and 3, the processing modules 12, 13 eachinclude a pair of top access doors 25 and a set of bottom access doors26. As with the access doors for the other modules, the access doors 25,26 when closed, facilitate the maintenance of desired internalatmosphere regulation, as it relates to the heating and cooling in thecrystallizing process. The access doors 25, 26 also provide a safetyshield for the operator when closed and provide access to the internalmachinery when opened.

Referring now to FIGS. 2 and 4, the drive mechanism for the crystallizermachine is located in the preheat pickup and drive module 10. The drivemechanism includes a motor 27 engaged with a drive shaft 28 through agear reducer 29. The drive mechanism further includes a brake assembly,detailed in FIG. 9, composed of a disc brake rotor 30 fixed to the driveshaft 28, brake shoes 31, and brake actuator 32. A drive sprocket rotarycam 33 is engaged with the drive shaft 28 and a drive sprocket 34 isalso engaged with the drive shaft 28 through coupler 35. A secondarydrive shaft 36 is engaged with the drive sprocket 34 and receives driveforces imparted by the drive motor 27 through the drive shaft 28 andcoupler 35. The secondary drive shaft 36 provides driving forces throughthe 90° gear box 37 to a timing belt drive pulley 38.

Referring now to FIGS. 8-12, the timing belt drive pulley 38 is engagedwith a timing belt driven pulley 39 by drive timing belt 40. Thus, drivepower is imparted from the drive motor 27 to the in-feed apparatus,shown in detail in FIGS. 9-12, by the in-feed drive shaft 41. Thedetails of the in-feed mechanism will be discussed below.

Referring to FIGS. 2, 4, 5, 6, 8 and 13, the transport member is shown.A top rail 42 is aligned with the drive sprocket rotary cam 33 and atakeup traction wheel rotary cam 43 which is located in the takeupmodule 11. The top rail 42 extends the full length of the crystallizingmachine. A bottom rail 53 is aligned with the drive sprocket 34 andextends the full length of the crystallizing machine to a lower takeuptraction wheel 44, also located in the takeup module 11. The takeuptraction wheel rotary cam 43 and takeup traction wheel 44 assembly isjoined together by a shaft 45 mounted in a spherical bearing which isbolted to a frame member 46. The frame member 46 is mounted on a slidebar frame 47. A pneumatic piston actuator 48 is engaged with the framemember 46 and provides a positive force against the frame member 46,thereby tensioning the takeup traction wheel rotary cam 43 and tractionwheel 44 assembly to provide full tension and takeup on the plug carrier49 which is engaged between the drive sprocket 34 and the lower takeuptraction wheel 44.

Referring now to FIGS. 9-12, the preheat, pickup and drive module 10 isshown in detail. Viewing FIG. 9, the drive sprocket rotary cam 33 is inalignment with the top rail 42. Cam follower members 50 are engaged withthe top rail 42 for guided travel thereon around the machine. Referringto FIGS. 2, 4, 5 and 6, it can be seen that the cam follower members 50will travel along the top rail 42 from the drive sprocket rotary cam 33,past the takeup traction wheel rotary cam 43 and return to the drivesprocket rotary cam 33. The drive sprocket rotary cam 33 is elevated inrelation to the top rail 42 for reasons set forth below. Each camfollower member 50 carries an elongated quill 51 at the end of which isa plug 52 which is preferably composed of a coated metal, such as hardcoat anodized aluminum. Drive sprocket 34 and lower takeup tractionwheel 44 are in alignment with the bottom rail 53. A plug carrier 49 isfixed to travel on the bottom rail 53 as it is driven by the drivesprocket 34. The plug carrier 49 includes a plurality of cam members 56which ride on the bottom rail 53. The plug carrier 49 also includes aplurality of openings, preferably two per plug carrier link throughwhich the quills 51 extend. Workpiece strippers 55 are fixed to the plugcarrier 49 in alignment with the openings and the quills 51 and plugs 52extend therethrough. Each workpiece stripper 55 and its respective quill51 and plug 52 have matching centerlines. The plug carrier 49 providesthe drive movement to the combined plurality of top cam follower members50 and attached quills 51 and plugs 52 and bottom cam members 56 withworkpiece strippers 55. The top cam follower member 50 and top rail 42combination provides vertical centering for the plug 52 and the bottomcam member 56 and bottom rail 53 combination provides horizontalcentering for the plug 52. Thus, the plug centerline is maintained onvery rigid vertical and horizontal axes.

The top rail 42 is designed to have a first elevated portion 54 locatedon the left side of processing module 12, as shown in FIG. 6, and asecond elevated portion 101, shown in FIG. 4, located on the left sideof the preheat, pickup and drive module 10, which aligns the rail 42with the drive sprocket rotary cam 33. The top rail 42 also includes aninclined portion 102 which immediately follows the drive sprocket rotarycam 33 located on the right side of the preheat, pickup and drive module10, as shown in FIGS. 2 and 9. In operation, it can be seen that whenthe cam follower members 50 with attached quill 51 are traveling alongthe top rail 42 around the drive sprocket rotary cam 33, the respectiveplugs 52 are pulled up and positioned within the workpiece stripper 55.As each cam follower member 50 with attached quill 51 travels down theinclined portion 102 of the top rail 42, the quill 51 gradually isextended through the workpiece stripper 55, thereby positioning the plug52 to a predetermined location below the workpiece stripper 55. It is inthis position that the plug 52 engages the workpiece to carry it throughthe processing operations of the crystallizing machine. After theworkpiece is fully processed, the cam follower member 50 travels up thefirst elevated portion 54 of the top rail 42 which pulls the plug 52 upinto the workpiece stripper 55, thus forcing the workpiece to be removedfrom its engagement of the plug 52. The finished workpiece is thenremoved from the crystallizer machine by the exit conveyor 103, shown inFIGS. 3 and 6. As the cam follower member 50 continues to travel alongtop rail 42, it exits the first elevated portion 54, moving to a lowerposition, thereby extending the plug 52 from the workpiece stripper 55.The plug 52 is then preheated by heat lamps 96, as will be described indetail later herein. As the cam follower member 50 travels up the secondelevated portion 101 of the top rail 42, the preheated plug 52 isretracted into the workpiece stripper 55. The cam follower member 50 iscarried by the drive sprocket rotary cam 33 to the inclined portion 102of the rail 42. As the cam follower member 50 travels down the inclinedportion 102, the preheated plug 52 extends out of the workpiece stripper55 to engage a new workpiece.

Referring still to FIGS. 9-12, the in-feed apparatus is shown in detail.The in-feed apparatus is positioned within the preheat pickup and drivemodule 10 to feed workpieces 57 into engagement with the preheated plug52. The in-feed apparatus includes a support frame 58 which carries adrive shaft 41 mounted in bearings 59. The drive shaft 41 has the driventiming belt pulley 39 fixed on one end which is engaged with the drivetiming pulley 38 by the drive timing belt 40 which receives input fromthe secondary drive shaft 36 as shown in FIG. 8. A pair of opposedsupport blocks 60 are fixed for movement on rods 61 which are mounted onthe support frame 58. The support blocks 60 are capable of movementtoward and away from each other on the rods 61 in order to accommodatedifferent size workpiece. Located between the support blocks 60 is aconveyor belt and platform 62 which carries bottles or workpieces from afeed bin (not shown) which is positioned adjacent the crystallizermachine of this invention. The conveyor 62 aligns the workpieces formovement through the in-feed apparatus. Each support block 60 carries adrive sprocket 63 mounted on a phase adjustable hub 64 and bearinghousing 65. The drive sprocket 63 receives drive input from the driveshaft 41 through 90° bearings 66 and drive shafts 67. Located at theends of the support blocks 60 in opposition to the drive sprockets 63are takeup sprockets 68. The takeup sprockets 68 are mounted on keyedbearing hubs 69 positioned in a slot located in the support block 60.Air cylinders 70 are fixed to each keyed bearing hub 69 to provide apositive force against takeup sprockets 68 and thereby create tension onthe cleated chain 71 which is engaged by each set of drive sprockets 63and takeup sprockets 68. The cleated chain 71 is composed of a chainmember 72 having cleats 73 attached thereto. The cleats 73 areadjustable on the chain member 72 and can be positioned to providediffering centerlines to adapt the cleated chain 71 to different sizeworkpieces entering the in-feed apparatus. The cleated chains 71 aredriven through the drive shafts 67 and drive sprockets 63 inrotationally opposite directions to provide movement in coordinationwith the moving conveyor belt 62, thereby centering the workpieces 57 inalignment with the centerlines of the plugs 52 which are in positionabove the in-feed apparatus. Thus, as each quill 51 and plug 52 isextended in a downward direction by the cam follower members 50traveling down the inclined portion 102 of the top rail 42, the plugwill cleanly engage the open mouth of the workpiece as shown in FIG. 9.

A stop 74 driven by a pneumatic air cylinder 75, shown in FIGS. 10 and12, is positioned at the mouth of the in-feed conveyor 62 to preventmovement of workpieces into the cleated chain 71 area duringnon-operation of the crystallizing machine and shutdown of the in-feedapparatus. A bump bar 76, shown in FIG. 10, is positioned at the end ofthe conveyor belt 62 where the workpieces 57 engage the plugs 52. Thebump bar 76 provides an upward force on the surface of the conveyor belt62 which acts to firmly press and seat the workpiece 57 onto the plug52. The bump bar 76 is driven by a cam member 77 engaged by a belt 78 toa drive pulley 79. The drive pulley 79 receives its drive from the driveshaft 41 through a 90° bearing 80 and drive shaft 81. A conveyor headpulley 82 is also positioned to receive drive from the drive shaft 81.The conveyor belt 62 is driven by the conveyor head pulley 82 and iscarried by pulleys 83, including takeup pulley 84 which is tensioned byan air cylinder 85.

Also positioned on support frame 58 is an in-feed workpiece stripper 86,shown in FIGS. 10 and 11, composed of a pair of cushioned rollers 87mounted on an adjustable support block 88 and driven by drive shafts 89which receive input through 90° bearings 90 attached to the in-feeddrive shaft 41. Infrared or dielectric sensors (not shown) are used toindicate whether the workpiece 57 has been firmly engaged with the plug52. If the workpiece is not firmly engaged with the plug 52, the in-feedworkpiece stripper 86 is activated and the rollers 87 engage theworkpiece and remove it from the plug 52.

Referring now to FIG. 13, and FIGS. 2, 4 and 5, the heating and coolingapparatuses of the crystallizer machine of the present invention aredetailed. FIG. 13 shows a back elevation view of the crystallizermachine showing the top rail 42 and bottom rail 53 which carry the camfollower members 50, 56, quill 51, workpiece stripper 55 and plug 52.FIG. 13 also shows the blower 16 for supplying cooling air to thecooling air plenum 22 which in turn supplies the cooling air to thecooling air duct 91 located at the bottom of the crystallizer machine.The cooling air duct 91 runs the length of the machine and suppliescooling air to the individual air knives 92 through adjoining duct work93. Positioned in the duct work 93 are individual valve controls 94which are used to regulate the amount of cooling air traveling to eachset of air knives 92. Referring to FIGS. 15 and 16, the cooling airknives 92 include nozzles 95 which are rotatably mounted on the ductwork 93. The duct work 93 includes flexible joints 104. Thus, thenozzles 95 may be adjusted by rotation and by movement of the duct work93 about the joints 104 to adapt to differing sizes of workpieces.Referring to FIG. 15, the structure wherein the cooling air knives 92are used in cooperation with heat sources to provide crystallizingtemperature and cooling temperature simultaneously is shown. Positionedimmediately above the air knives 92, as shown in FIG. 15, are heat lamps96 positioned within reflectors 97. The heat lamps 96 are used to applyheat to the finish area of the workpiece 57 to cause crystallizationthereof while the air knives 92 are intended to cool the workpiece 57immediately below its finish area to prevent crystallization thereof.Finally, in the preheat section of the preheat pickup and drive module10, as shown in FIGS. 4 and 14, the heat lamps 96 are used to preheatthe plug member 52 and no air knives are in operation. Thus, inoperation, the plug member 52 is preheated prior to insertion into themouth of the workpiece. The workpiece then travels past the heat lamps96 and air knives 92 such that the finish area of the workpiece receivesheat from the preheated plug 52 and the heat lamps 96 to crystallize thefinish area. The workpiece finally passes the cooling air nozzle asshown in FIG. 16 prior to exiting the machine.

Referring now to FIGS. 2 and 5, the right side elevation of thecrystallizer machine of the present invention is shown. The processingmodules 12 and 13, shown in FIG. 5, and the takeup module 11 include aplurality of the heat lamps 96, reflectors 97, and air knives 92, asshown in FIG. 15, which extend the full length on the right side of theprocessing modules 12 and 13 and up to a point proximate the takeupwheels 43, 44 of the takeup module 11. To ensure a full understanding ofthe Figs., the air knives, heat lamps and reflectors are only partiallyshown in number in the Figures. The plug 52 is preheated to atemperature of between 150° F. to 170° F. prior to insertion into themouth of the workpiece 57. As the preheated plug 52 carries theworkpiece past the heat lamps 96 and reflectors 97, the finish area ofthe PET workpiece is gradually heated to a crystallizing temperature ofapproximately 350° F. while the air knives 92 maintain the remainder ofthe body of the workpiece cool.

Appropriate sensors (not shown) are located throughout the crystallizingmachine and are used to monitor the temperature of the preheated plug52, monitor the proper seating of the mouth of the workpiece 57 with theplug 52, monitor the exhaust heat and monitor the cooling airtemperatures. Other sensors may be used throughout the system asdesired. All sensors provide signals to a central processing unit (notshown) which coordinates the operation of the crystallizing machine. Hotair is removed from the crystallizing machine through the hot air plenum21 and exhausted to atmosphere.

To provide even preheating of the plug 52, the quill 51 has a gear 98positioned immediately above the plug 52 which engages a stationary geardrive member 99, as shown in FIG. 14. Movement of the workpiece andengagement between the gear 98 and stationary gear drive 99 causes theplug 52 to continually rotate as it moves past the preheat sources,thereby providing even heat application to the surface of the plug 52.As shown in FIGS. 15 and 16, the engagement between the gear 98 and thestationary gear drive member 99 will impart continuous rotation to theworkpiece engaged with the plug 52 as it travels past the various heatsources and cooling sources.

Referring now to FIGS. 4 and 6, the left side elevation of the takeupmodule 11 includes air knives 92 without heat lamps 96 as shown in FIG.16. Cooling of the crystallized PET workpiece is effected by directingcool air from the air knives 92 over the entire workpiece 57. Theworkpiece continues to pass by cooling air knives 92 located on the backof the processing module 13 and part of the processing module 12 untilthe workpiece is removed and directed down the exit conveyor 103 locatedin processing module 12, as shown in FIGS. 3 and 6. After the workpieceshave been removed from the plug 52, the plug 52 passes the preheatingsource consisting of heat lamps 96 and reflectors 97 without air knives,as shown in FIG. 14 to effect preheating of the plugs 52.

Referring now to FIG. 17, the preferred embodiment of the plug 52 isshown. The plug 52 is essentially a hollow shell constructed of hardcoat anodized aluminum. The shell construction allows for rapidpreheating of the plug 52. An engagement aperture 105 is positioned onthe centerline of the plug 52 to receive the quill 51 and attach theplug 52 thereto by conventional means. The outside diameter D of theplug 52 closely approximates the inside diameter of the mouth of theworkpiece to provide a snug secure fit when the plug 52 is inserted intothe mouth of the workpiece. The plug 52 tapers inward and downward fromthe outside diameter D to a smaller diameter d which assists the plug 52to be inserted into the mouth of the workpiece. Flexible wire springs100 are positioned about the tapered portion of the plug 52, defining anoutside diameter slightly larger than diameter D. The wire springs 100flex when inserted into the mouth of the workpiece and expand to exertforces on the interior of the workpiece, thereby assisting in securingthe workpiece on the plug 52.

The above description of the preferred embodiment of the crystallizermachine of this invention is intended to be illustrative in nature andis not intended to be necessarily limiting upon the potentialequivalents when determining the scope and content of the followingclaim.

We claim:
 1. A crystallizing machine for processing a thermoplasticworkpiece having a mouth or opening at one end comprising incombination: at least one plug for engagement with the mouth of theworkpiece(s) and means for moving the at least one plug and its engagedworkpiece(s) through the crystallizing process steps; at least one heatsource for applying heat to the workpiece(s) to heat the workpiece(s) toa temperature at which the thermoplastic crystallizes; and adisengagement member for removing the workpiece(s) from the at least oneplug.
 2. The crystallizing machine of claim 1 further including at leastone cooling source for cooling the heated thermoplastic aftercrystallization.
 3. The crystallizing machine of claim 1 wherein the atleast one plug solely supports the workpiece(s) in an upright position.4. The crystallizing machine of claim 1, wherein the at least one plugis heated prior to engagement with the workpiece(s).
 5. Thecrystallizing machine of claim 4 wherein the thermoplastic iscrystallized by the at least one heated plug and the at least one heatsource.